How to Delete the Windows.old Folder in Windows 10

To delete this folder, use the Windows Disk Cleanup tool. On Windows 10, click the Start button, search for “Disk cleanup” in the Start menu, and launch the Disk cleanup application. You can also right-click the C:\ drive in File Explorer, select Properties, and click the “Disk Clean-up” button under the General tab.

Click the “Clean up system files” button. You’ll see “Windows Previous installation(s)” appear in the list, and Disk Cleanup will tell you how much space those files are taking up. Check that option and use Disk Cleanup to wipe the previous Windows system files away. You can also use this tool to wipe other unnecessary files taking up space on your system drive.